The present invention relates to an electrode for insertion into a body cavity, and in particular, to an electrode for insertion into a vagina for urinary incontinence treatment.
Urinary incontinence is a common problem throughout the world and is particularly prevalent in the female population and in the aged. A large number of women suffer from urinary incontinence due to childbirth or general deterioration of body structures as an aging process and so on. It is known that about 20-30% of women over 50 years old suffers from urinary incontinence. Resulting from urinary incontinence is embarrassment, discomfort and distress, loss of sleep and the necessity for large monetary disbursements by the patients for absorbent pads, diapers, rubber sheeting and for cleaning of soiled clothing.
These days the treatment for urinary incontinence includes surgery, physical rehabilitation and drug therapy.
The surgery treatment methods are invasive and thus most patients hesitate to choose this option over others. In addition, the drug therapies are known to provide very limited effectiveness. However, treatment for urinary incontinence is viewed differently by society as many non-invasive and non-pharmaceutical treatment methods are being introduced lately. Among such treatment methods, a biofeedback therapy and a neuromuscular electrical stimulation method are most commonly recognized as major treatment methods. These treatments have been proven very effective, safe to use and relatively inexpensive. In biofeedback therapy, repetitive contractions of pelvic floor muscles improve the strength of the pelvic floor muscles. Neuromuscular electrical stimulation method applies current pulses to pelvic floor muscles so that the motor nerve fibers are electrically stimulated. For more effective treatment for urinary incontinence, it is desirable that both the biofeedback and neuromuscular electrical stimulation methods are performed at the same time, rather than one of them being independently performed.
For the sake of performing such treatment methods, an electrode is needed for delivering electrical pulses to a vaginal muscle. This electrode is generally made in cylindrical shape suitable for insertion into a vagina. One example of this cylinder-shaped electrode is disclosed in U.S. Pat. No. 5,199,443. Referring to this, the electrode is formed cylindrically, non-conductive polymer bands and conductive polymer bands alternatively disposed. Here, the conductive polymer band is used to deliver electrical signals to the vaginal muscle or detect an EMG signal from the vaginal muscle. Accordingly, the conductive polymer band is necessary to be coupled to an external device that generates electrical signals and this connection is made with sockets and electrical wires. Although the conductive polymer bands are in general more comfortable to insert into the vagina than metal bands, the conductivity of the polymer band is much lower than that of the metal band. Thus, to improve the transfer characteristics of the electrical signal, multiple band-type of metal rings are inserted at the inner circumference of the conductive polymer bands. More specifically, in the electrode disclosed in U.S. Pat. No. 5,199,443, the diameter of the metal rings are slightly larger than the inner diameter of the conductive polymer band and the metal rings are also discontinuous, which gives the metal rings resilient force. This resilient force of the metal rings causes the electrical/mechanical connection to be supported between the conductive polymer bands and the metal ring.
However, problem exists in that this connection is very week against an external mechanical impact because the inner part of the electrode is hollow, so that making such electrode is very little plausible. Moreover, even though the electrode is manufactured, because the electrode should be very frequently inserted into the vagina, the conductive bands and the metal rings are likely to become electrically disconnected by mechanical impact accompanied with the insertion.
In addition, for such electrodes, the front end and the rear end are separately formed in cap shape and then coupled to the main member, for example, by adhesives or the like, which results in reducing the durability at the cap connection portion. Further, since the electrode for insertion into a vagina requires to be very frequently washed, if any crevice at the cap connection portions, water and disinfectant are apt to permeate through the crevice. Also, the hollow of the electrode decreases the durability as well as increases the possibility of an electrical shock accident in case of the water leakage through the cap crevice.